I. Field of the Invention
The present invention relates generally to a system for selectively and temporarily storing parts from an industrial assembly line and then subsequently reintroducing the parts into the assembly line.
II. Description of the Prior Art
Modern industrial assembly lines typically contain a number of sequential stations along the assembly line. A work operation, assembly, machining operation or the like is typically performed at each station along the assembly line.
During a typical operation of the assembly line, one or more stations may be temporarily inoperable. For example, it may be necessary to replace the tooling at a particular station and during that changeover, the station is inoperable. Likewise, a malfunction or breakage at the assembly station may render the station inoperable for a period of time.
It is not economically practical to shut down the entire assembly line whenever a station becomes inoperable. Consequently, whenever a station becomes inoperable, it has been the previously known practice to manually temporarily store the parts on the assembly line upstream from the inoperable station until the station is again operable. When that occurs, the normal flow of parts along the assembly line through the workstation is reestablished. Thereafter, when the supply of parts to that particular workstation is interrupted for any reason, e.g. the temporary failure of an upstream workstation, the previously stored parts are then reintroduced into the station so that the normal flow of parts through the station, as well as downstream workstations, continues.
A primary disadvantage of this previously known method for maintaining the flow of parts along an industrial assembly line is that the manual temporary storage of parts and the subsequent manual reintroduction of those parts into the assembly line is necessarily labor intensive and, therefore, expensive.
The present invention provides an automatic system that overcomes all of the above-mentioned disadvantages of the previously known methods.
In brief, the present invention comprises a first and second conveyor wherein each conveyor has both a first end and a second end. A robot manipulator is positioned adjacent to the assembly line and also adjacent the first ends of the conveyors. This robot manipulator, furthermore, is configured to selectively engage and release parts of the type conveyed by the assembly line.
The system of the present invention further comprises a plurality of containers wherein each container is adapted to receive a plurality of parts in predetermined positions within the container. Preferably, the containers are stackable to a predetermined height, e.g. five containers.
In order to accurately position the container relative to the conveyor, and thus relative to the robot manipulator, an alignment rail is provided along one corner at the first end of each conveyor. An actuator is then mounted cross corner from the container and movable between an extended and a retracted position. In its extended position, the actuator engages and moves the container against the alignment rail thus accurately positioning the container. Conversely, in its retracted position, the actuator is moved away from the container and allows the containers to be moved by the conveyors.
A controller selectively controls both the activation and direction of movement of both conveyors, as well as the operation of the robotic arm. The controller also controls the activation of the actuators.
In practice, the system is positioned upstream from a workstation along the assembly line which, in turn, is normally supplied parts from workstations upstream from the system. Assuming that the assembly line provides an uninterrupted flow of parts to the workstation and that the workstation is operable, the system of the present invention stands idle.
However, in the event that the workstation becomes temporarily inoperable, empty containers are conveyed to the first end of the second conveyor. The robotic arm then moves an empty container from the second conveyor and onto the first end of the first conveyor. The controller then actuates the actuator to position the empty container at a predetermined position at the first end of the first conveyor whereupon the robotic manipulator fills the container with parts supplied on the assembly line to the temporarily inoperable workstation.
Assuming that the workstation remains inoperable for an extended period of time, after the robotic actuator fills one container, it positions an empty container from the second conveyor on top of the filled container on the first conveyor and then fills that container. That process is repeated until the filled containers at the first end of the first conveyor are of a predetermined height, for example a stack of five filled containers. At that time, the controller actuates the first conveyor to move the filled containers to the second end of the first conveyor and simultaneously activates the second conveyor to move a new stack of empty containers to the first end of the second conveyor whereupon the above process is repeated. Furthermore, while the robot manipulator fills parts into the empty containers in the above-described fashion, the stack of filled containers is removed from the second end of the first conveyor by conventional means, such as a forklift truck, while, similarly, a stack of empty containers is positioned on the second end of the second conveyor.
The above process is repeated until the normal flow of parts through the workstation is reestablished. However, in the event of an interruption in the supply of parts to the workstation, the above process is simply reversed. More specifically, the robot manipulator removes parts from filled cartons at the first end of the first conveyor and reintroduces these parts into the assembly line. Once a container is empty, the robot manipulator moves the empty container from the first end of the first conveyor and to the first end of the second conveyor. A stack of filled containers is also positioned at the second end of the first conveyor.
After the robot manipulator has removed all of the parts from the stack of filled containers at the first end of the first conveyor and stacked the empty containers at the first end of the second conveyor, the controller actuates the conveyors to move a fresh supply of new filled containers from the second end and to the first end of the first conveyor and, simultaneously, to move the stack of empty containers from the first end of the second conveyor and to the second end of the second conveyor. The above process is then repeated.